textproduct: Rapid City

KEY MESSAGES

- Very hot temperatures will continue through much of next week, with record high temps possible and dangerous heat.

- Near-critical to critical fire weather conditions will continue into next week.

UPDATE

Issued at 931 PM MDT Sat Jul 11 2026

03z surface analysis had lee trough from central MT into western CO and high over the Great Lakes. Modest pressure gradient inbetween with southerly flow over the CWA. Water vapour loop had robust upper ridge over WY/UT/CO. 00z KUNR sounding tells the story - hot dome in place over the CWA.

Latest guidance shows little relief in sight through most of next week. Robust upper/thermal ridge moves little over the northern Plains bringing dangerous heat and very dry air per deep boundary layer mixing. Breezy spots likely Sunday given surface pressure gradient/mixing, but uncertainty increases Monday as lee trough shifts east which may tamp down gusts in the west. Thus, current Red Flag Warning looks good for Sunday. As far as heat headlines, Heat Advisory paints danger well with peak apparent temperatures near 105F. However, we may approach the 4-day mark for Extreme Heating Warning criteria (max apparent temps 100F+) by Wednesday given latest ensemble guidance trends, so we'll keep an eye on that. Some folks might see actual temperatures of at least 100F through next Friday.

DISCUSSION

(This Evening Through Saturday) Issued at 233 PM MDT Sat Jul 11 2026

Very strong ridging is building into the Great Basin and northern Plains today...and will continue to strengthen over the region on Sunday through the first half of next week. Right now...surface obs show temps in the upper 90s to lower 100s across most locations. Across the Black Hills...temps are in the upper 80s to mid 90s. KUNR has reached 101F in the last 30 minutes, which sets a new daily record high. Satellite and KUDX radar show isolated convection developing across the northern Black Hills. No lightning strikes have seen, but could see a few strikes before precip dissipates late this afternoon. It does appear this precip is reaching the ground, which is helpful considering the dry lightning concern. S/SW flow will continue to bring very hot temperatures to the area over the next several days. Daily H70 temps of 15-20C will bring temps well above 100F through Tuesday...and now Wednesday and possibly Thursday, as models are increasing temps for the second half of the week. Future shifts will need to consider extending heat-related headlines. No precip is expected until at least Thursday.

AVIATION

(For the 12Z TAFS Through 12Z Monday Morning) Issued At 535 AM MDT Sun Jul 12 2026

Expect VFR conditions through the forecast period. Gusty south/southeast winds will develop this afternoon, strengthening tonight due to a tightening surface gradient.

FIRE WEATHER

Issued At 233 PM MDT Sat Jul 11 2026

Strong high pressure over the region for the next several days will bring very hot temperatures to northeastern Wyoming and western South Dakota, along with dry air and breezy winds. On Sunday, winds will gust up to 35 mph, which combined with the very low humidity of 15% or less, will result in critical fire weather conditions across the northeastern Wyoming and far western South Dakota plains. A Red Flag Warning has been issued for Sunday. Will continue to monitor the potential for critical fire weather conditions next week, which may require extending the Red Flag Warning additional days.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Heat Advisory until 8 PM MDT /9 PM CDT/ Tuesday for SDZ001-002- 012>014-025>027-030>032-041>044-046-047-049-072>078. Red Flag Warning from 10 AM this morning to 9 PM MDT this evening for SDZ322>327-329-332. WY...Heat Advisory until 8 PM MDT Tuesday for WYZ054>056-058>060. Red Flag Warning from 10 AM this morning to 9 PM MDT this evening for WYZ314>317.